* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    outline: none;
    text-decoration: none;
}

html,
body {
    margin: 10rem auto;
    width: 100vw;
    height: 100vh;
    min-height: 100vh;
    font-size: 16px;
    background-color: #212121;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

@property --deg {
    syntax: '<angle>';
    inherits: false;
    initial-value: 0deg;
}

#app {
    width: 40rem;
    height: 40rem;
    animation: ani-bg 10s linear infinite;
    filter: hue-rotate(var(--deg));
}

@keyframes ani-bg {
    to {
        --deg: 360deg;
    }
}

.loading {
    width: 10rem;
    height: 10rem;
    position: relative;
}

.loading span {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    /*background-color: yellow;*/
    transform: rotate(calc(18deg * var(--i)));
}

.loading span::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 0.5rem;
    height: 0.5rem;
    border-radius: 50%;
    background-color: #00ff0a;
    box-shadow: 0 0 0.6rem #00ff0a,
                0 0 0.8rem #00ff0a,
                0 0 1.0rem #00ff0a,
                0 0 1.2rem #00ff0a,
                0 0 1.4rem #00ff0a,
                0 0 1.6rem #00ff0a;

    animation: ani 2s linear infinite;
    animation-delay: calc(0.1s * var(--i));
}

@keyframes ani {
    0% {
        transform: scale(1);
    }

    80%, 100% {
        transform: scale(0);
    }
}